Rose Propagation - Ziplock Bag Technique

DOGGYBAG TECHNIQUE FOR STRIKING CUTTINGS IN WARM WEATHER.


Modified from a technique developed in the US by Mike Shoup. For a variant of this see http://www.rdrop.com/~paul/hulse.html  In theory this works for any plant that doesn’t have furry leaves, but our main success has been with roses.

Used from about mid-November to mid- February (as starting date, in southern Australia). In autumn, in-ground cuttings give better results.

Cut the bottom corners (about 1 - 2cm) from a zip-lock (food storage) bag - Coles’ 32 x 25cm or thereabouts. Put about 10cm depth of commercial seedling & cutting mix into the bag, or use a potting mix (eg Nu-earth Premium) with 1 -2 handfuls of an aerator – Vermiculite or Perlite, or for a tenth of the cost, Coles’ basic kittylitter (NOT clumping). (The writer does not otherwise shop at Coles.) Water it till the mixture is wet through, then close the bag and leave it to drain for several hours.
The cuttings should be from a stem that has flowered, up to a pencil-size diameter (old-rose rescuers generally have to use much smaller bits.) (For climbers, the cutting should be from a climbing shoot.) Cut off the top bud. Take the leaves off the bottom 2 or 3 nodes (which will go into the potting mix), and keep some of the leaves on 2 or 3 upper nodes. (Leafless pieces are much slower, and less likely to succeed.) Re-cut the stem obliquely a little below the lowest node, and dip it immediately into a rooting hormone (some people use honey). Make a hole in the potting mix almost to the bottom of the bag, and put the cutting into the hole. A bag will take 3-4 cuttings. Close the bag, and write the name and date on the outside of the bag with a Garden Marker pen, where they are easily seen. It is not a good idea to put cuttings of different roses into the same doggybag; it’s too easy to mix them up.

The bags should be put where they will receive light but not direct sunlight. They can be put in groups standing in a cat-litter tray (from an el cheapo store), so they will support each other and are less likely to be knocked over. ( 3-5 per tray, depending on size.) A clear container is better, so you can see roots developing without moving the bags. It’s essential that the drainage holes aren’t blocked. It’s important not to disturb the developing roots,  but the bag can be opened from time to time to remove fallen leaves or flower buds or dead cuttings (make sure it is sealed properly again afterwards). (You can blow into the bag to plump it up.)

If you can’t see many droplets of moisture on the inside of the bag after a while, add a teaspoon or two of water, but this is rarely necessary.

When good roots are visible in the bottom of the bag (and not before), leave the bag unsealed for a few days to harden off the plant (it may need some water). Then it can be potted out, scooping out a handful of soil around the roots. (Loss rate from potting out is about 1 in 12 – higher if you take them out before the roots are fairly well-developed.) Tiny new leaves usually wilt straight away, and may be better removed. The plant will be top-heavy, and will need shelter from wind for some weeks. Introduce it gradually to sunlight over a couple of weeks. Feed weekly with dilute Seasol alternating with a diluted fertiliser containing trace elements, eg Phostrogen, until it is planted out or potted on. Mulching of pots or in-ground plants is important.

As a rough guide: for rambler roses, you can start looking for roots at 3- 4 weeks; for Tea roses from about 6 weeks. HTs, especially the yellows, are much slower and have a lower success rate. The Old European roses (spring-flowerers) are harder to strike – it’s easier to dig up a sucker if they’re growing on their own roots (but they will sucker if planted on their own roots in the garden, and may become invasive. Rugosas and species roses similarly may become invasive if planted on their own roots. For these roses, it's preferable to get someone to bud them, or you can grow them in large tubs.).

The ziplock mechanism doesn’t last well enough to use the bag for a second batch.

An alternative technique is to use clear plastic glasses with drainage holes made near the bottom, putting the glasses into a clear plastic lidded storage box. This uses much less potting mix, and the roots are visible earlier, but they are more frail (because younger) when being potted out. For large numbers of cuttings (carefully labelled), the potting mix + aerator can be used in a broccoli box (some people plant them just into kittylitter, without potting soil).

MAY: in-ground cuttings work best, especially in areas which get some winter frosts. Longer cuttings than in doggybags are preferable, with at least 2 nodes in the ground, and most of the leaves removed. The larger the piece, the more stored carbohydrate it will have (up to pencil-thickness). They will need mulching, and twice-weekly watering  through the summer. It’s best not to dig them up till the winter of the following year.

Looking after baby roses. We suggest watering weekly through the first summer (preferably not overhead watering), fortnightly the second, monthly thereafter. This may need to be increased in heatwaves.
It’s best to remove almost all flower buds the first year, so the plant will put its energy into making roots and leaves. Any stressed plant does better with flower-buds (or developing fruit) removed.

Spraying; in general, most of us don’t. Milk/powdered milk diluted 1 in 10 can be used for mildew, or to protect soft new growth when a heatwave is predicted. Parasitic wasps can be bought, to deal with aphids.

Roses don’t like Roundup or whippersnippers.

Foundling roses are generally given a study name (within double inverted commas) based on where they come from (eg the district or the name on the nearest grave) or someone associated with the rose. If there is more than one unknown at the site, a descriptive term is helpful. Eg “Blakiston Pink Tea”.

It’s a good idea to keep a planting plan of your garden in case labels fade or disappear, and a record of where they came from.